Antarctica's Pine Island Glacier May Continue Thinning for Decades to Come

Geologists reveal that the massive Pine Island Glacier, one of the fastest flowing glaciers in Antarctica, may continue shrinking for decades to come.

A team of international geologists have discovered that the Pine Island Glacier (PIG), one of the biggest single contributors to the rising sea levels, has thinned rapidly before. The current acceleration in the glacier's thinning and retreat is expected to continue for several decades.

A team of geologists from UK, USA and Germany reveals that nearly 8,000 years ago the Pine Island Glacier on the West Antarctic Ice Sheet thinned as fast as it has in the recent decades. This thinning and retreating of the fastest moving glacier offers clues about future Antarctic ice loss.

According to the team, the sudden increase in the rate of thinning and retreat is due to the ocean- driven melting where large volume of warm ocean water reaches below the ice shelf.

Lead author Joanne Johnson from the British Antarctic Survey (BAS) said, "Our geological data show us the history of Pine Island Glacier in greater detail than ever before. The fact that it thinned so rapidly in the past demonstrates how sensitive it is to environmental change; small changes can produce dramatic and long-lasting results. Based on what we know, we can expect the rapid ice loss to continue for a long time yet, especially if ocean-driven melting of the ice shelf in front of Pine Island Glacier continues at current rates."

Geologists were alarmed by the rapid ice loss and were concerned over the extent of ice loss in the future. The model projections of the thinning of the PIG also leave a lot of questions unanswered regarding the rate of sea level rise, the timing and its persistence.

The geologists gathered evidence regarding the change in the past ice sheet from the rocks that were exposed to the retreating or thinning glaciers. Using advanced sensitive dating method, the geologists tracked the thinning of PIG and gathered data on the glacier that existed for several decades.

Professor Mike Bentley, a co-leader of the project based at Durham University said, "This paper is part of a wide range of international scientific efforts to understand the behaviour of this important glacier. The results we're publishing are the product of long days spent sampling rocks from mountains in Antarctica, coupled to some exceptionally precise and time-consuming laboratory analyses. The results are clear in showing a remarkably abrupt thinning of the glacier 8000 years ago."

Earlier this year, it was revealed that PIG entered into a self sustaining retreat raising the sea levels in the next 20 years. It would contribute to a 3.5-10 mm rise in sea levels.

The finding was funded by the Natural Environment Research Council and Lamont-Doherty Earth Observatory, USA.